1. Field of the Invention
The present invention relates to transformants producing secondary metabolites modified by functional groups, more specifically, to transformants producing secondary metabolites in which a benzene ring is modified at the para-position with a functional group containing a nitrogen atom. Furthermore, the present invention relates to novel genes involved in a biosynthetic pathway from chorismic acid to p-aminophenylpyruvic acid.
2. Description of the Related Art
Since organisms produce a number of various kinds of secondary metabolites having biological activity, research for utilizing these metabolites for drugs for humans and animals, agricultural chemicals, and the like has been actively carried out. However, secondary metabolites from organisms can rarely be utilized for practical use as they are, and accordingly they are generally modified with various functional groups to optimize their biological activity. A modification with a functional group containing a nitrogen atom, such as a nitro group and amino group, is one of the most important modifications.
Chemical methods are available for modifying a certain substance with a nitro group. However, introduction of a nitro group into a benzene ring specifically at the para-position using a chemical method is extremely difficult, and its yield is very low. Furthermore, when a substance to be modified with a nitro group is as complex as a secondary metabolite from an organism, it is even more difficult to specifically modify a benzene ring at the para-position with a nitro group.
On the other hand, methods of introducing an amino group are generally classified into two groups, i.e., enzymatic methods and chemical methods. In enzymatic methods, an enzyme called aminotransferase (EC 2.6.1 group) is used. However, substances which can be a substrate for the aminotransferase are limited, and no enzyme has been known to directly transfer an amino group to a benzene ring. Therefore, only chemical methods have been available for modification of a benzene ring with an amino group.
However, in chemical procedure, it is necessary to first modify a benzene ring with a nitro group and then to reduce this nitro group into an amino group. Since the nitration reaction in the first step is very difficult, introduction of the amino group into the benzene ring by chemical methods is extremely difficult. Accordingly, development of a method of modifying a benzene ring specifically at the para-position with a nitro group or an amino group has been strongly needed.